Technical Abstract:
Effective sampling range is defined as the maximum distance from which an insect can reach an attractive source in a given period of time. Information on sampling range is valuable for determining appropriate coverage of traps for use in population delimitation, mass trapping control strategies, or identification of foci of infestation for precision targeting of control measures. Despite extensive use of protein-based female-targeted attractants in current trapping programs for tropical tephritids, there is little documentation their effective sampling range. Studies were conducted in Florida and Honduras. A geostatistical analysis approach, using data from capture of wild flies in a specifically designed trapping grid, were compared with a standard release/recapture study approach that used laboratory-reared sterile and wild flies (Florida), and recently captured wild flies (Honduras) to determine effective sampling range. Field design consisted of 38 traps (over 0.5 ha) placed in a combination of standard and high density grids to facilitate geostatistical analysis, and tests were conducted in coffee, mango and orthanique with the three component lure (APT: ammonium acetate, putrescine, trimethylamine, Honduras) and guava with the two component lure (AP) and torula yeast/borax (TY, Florida). Effective sampling range, as determined by geostatistical analysis for APT for C. capitata, was ~30 m for flies captured in coffee or mango and ~ 40 m for flies captured in orthanique. Similar results were obtained from the release/recapture study, and contour maps indicated that wind direction had a strong influence on sampling range, which was ~15 m greater upwind as compared to downwind from the release point. In release/recapture tests with mature wild A. suspensa, range of AP was determined to be 30 m. With sterile females, effective range of both AP and TYB was 20 m. Sterile immature A. suspensa females dispersed farther and were recovered in higher numbers than mature females, and recapture with AP was higher than recapture with TY. Geostatistical analysis of field-captured insects in appropriately designed trapping grids may provide a supplement or alternative to release/recapture studies to estimate sampling ranges for semiochemical-based trapping systems. Contour maps indicated that wind direction had a strong influence on the active space of attractants, as reflected by distribution of captured flies in release/recapture studies.